This invention relates to a propeller for a boat, and, more particularly, to a propeller which eliminates cavitation and provides continuous propulsion.
Many boat propellers suffer from one or more disadvantages. For example, some propellers cause cavitation, some do not provide positive propulsion at all times, and some become relatively easily fouled by weeds and other obstructions.
Propellers formed in accordance with the invention eliminate these problems. The propeller includes a blade which is helically disposed around an elongated shaft, and the outer periphery of the blade undulates to form three vanes which are spaced about 120.degree. apart around the circumference of the shaft. The blade merges with the shaft between the vanes and in effect disappears so that the propeller can rid itself of weeds or other obstructions. The blades are spaced axially along the shaft and provide continuous, positive propulsion at all times and eliminate the problem of churning in one spot that is inherent in some propellers. The shape of the propeller also eliminates cavitation.